Introduction to Cooled Semen

Breeding with Cooled, Transported Semen (TS) is Here to Stay.

Note: The airlines have enacted new guidelines for shipping counter-to-counter on commercial airlines. Call your airline for more information.

As of December 2000, the vast majority of equine breed registries, in the U.S. and internationally, has approved the use of transported semen. Because of this, it is highly likely that most equine breeders will need to either ship stallion semen or to use transported semen to inseminate their mares at some point in the future.

While the collecting, processing and inseminating of cooled semen is fairly straightforward, proper preparation is essential. Optimal success rates require knowledgeable personnel on both the shipping and receiving sides of the equation. Just one "weak link" in the chain of events can make the difference between a mare in foal and a lost opportunity. This section of our website is dedicated to providing information to both the stallion and mare owner to help strengthen your transported semen breeding program so you may achieve the success you desire.

Background of Cooled Semen

Results using Cooled Semen

Cooled, transported semen (TS) was first successfully used in a 1983 field trial at Hamilton Farm (South Hamilton, MA). Results of the field trial (50 mares, 3 stallions) indicated that TS can achieve conception rates equal to those on the best farms. Cumulative statistics per cycle showed the following:

1st cycle total percentage of mares in foal = 62%
2nd cycle total percentage of mares in foal = 82%
3rd cycle total percentage of mares in foal = 90%
Since then, breeding farms around the world have been using TS with similar results.

The Cooling Rate is the Key

Because sperm are highly susceptible to "cold shock," cooling the semen at the proper rate is necessary to prevent irreversible damage to the sperm. The Equitainer was designed to provide a controlled environment that gradually cools the extended semen sample at a rate of -0.05°C/min down to a minimum temperature of approximately 4°C. It then maintains the sample at the proper refrigerated temperature for up to 70 hours while also preventing freezing of the sample. It is critical that the sample does not freeze during shipment. While freezing is an alternative for long distance breeding, the process involves specialized equipment and a strict protocol.

Use of a Semen Extender is also Necessary

Extender, to which antibiotics have been added, provides nutrients to the sperm and prevents growth of bacteria. If extender is not added to the semen sample within 15 minutes, sperm survivability is drastically reduced. In addition to maintaining sperm viability, there is another advantage of using extender. Diluting the ejaculate allows multiple mares may be bred from a single ejaculate (providing the raw ejaculate has a sufficient sperm concentration).

Benefits of Cooled Semen

Cooled Semen has Numerous Benefits for Both the Mare Owner and Stallion Owner

Benefits to the Mare Owner

Reduces Stress and Risk of Injury
Mares with young foals or mares that are difficult shippers do not need to be exposed to the stress of shipping to the stud farm. Also, the risk of injury during shipping or while boarded at the broodmare facility is removed. With transported semen, mares can be bred in the comfort of their own home and do not run the risk of slipping the foal when shipped home.

Choice of Stallions not Limited to Location
Before transported semen, mare owners were limited to stallions located within a reasonable shipping distance. Thanks to transported semen, breeding can be based on choosing the best stallion for your mare. This also enhances the genetic pool within geographic areas by opening the door to a wider selection of stallions.

Mare Owners are Involved
In addition to the convenience of keeping your mare at home, mare owners gain more personal satisfaction by becoming an integral part of the breeding process.

Monitor Quality of Sperm
Mare owners can see the quality of sperm being inseminated.

Reduction of Disease Transmission
Chance of transmission of venereal and other communicable diseases is reduced.

Benefits to the Stallion Owner and Stud Farm

No Broodmare Care Required at the Stud Farm
Stud farms no longer need to board broodmares during the breeding season. This decreases the burden on the stud farm to accommodate multiple broodmares and ultimately reduces operating costs and enhanced profitability.

More Efficient Scheduling of the Stallion
With the ability to split ejaculates and store semen, stallions do not have to be collected numerous times per day.

Small Breeders also Benefit
Owners with only one or two stallions can manage their stallions at home and avoid costly collection centers. Stallions can remain at home, stay in work and continue competing.

Reduction of Disease Transmission
Chance of transmission of venereal and other communicable diseases is reduced.